Hi
I normally don't worry until the next meal as the result will depend on factors such as how much I've eaten (and dosed), exercise I'm planning to do, etc.
I think the advice is often for about 8, 2 hours after though. What I look at is the result once all the carbs and insulin have cleared (I'm using Apidra as a bolas dose which is fast) at the next meal (4+ hours) which should be a clean baseline if I've got it right previously. It's nice to get 4.5-6 for these readings.
It's something you should discuss with whoever is helping you with your dosing.